1. Field of the Invention
The invention relates to a system for moving a headrest assembly of a vehicle seat upward and forward in the event of a rear impact.
2. Background Art
Improvements in safety mechanisms in the automotive industry continue to be made year after year. One example of such a safety mechanism includes a safety headrest as disclosed in U.S. Pat. No. 5,378,043. Headrests are provided to support the head of an occupant during a collision.
In a rear impact, a vehicle seat occupant may be driven rearwardly to exert a reaction force on the vehicle seat back. The pelvis and buttocks region of an occupant generally exerts more force initially on the seat back than the shoulder region of the occupant. This initial load applied by the pelvis and buttocks of the occupant may cause the seat back to be deflected rearwardly. As the seat back moves rearwardly, separation between the seat back and an occupant""s head and torso may be increased.
In an attempt to solve this problem, active headrest mechanisms have been proposed in which the occupant""s torso applies a rearward load or force to an impact target in the vehicle seat. The impact target is connected to a headrest cushion portion that moves forward upon application of a rearward load on the impact target. The cushion portion moves forward toward the head of the occupant to lessen the gap between the head of an occupant and the headrest cushion portion in a collision.
According to one aspect of the present invention, an improved vehicle seat and active headrest assembly combination is provided. The active headrest is activated by the application of a rearward pelvic load or force to the lower portion of a seat back by an occupant in a rear impact. The assembly includes a seatback frame and a dynamic headrest assembly support that moves the headrest in an upward and forward direction. The headrest assembly support includes a pivotal lower target that is oriented to be contacted by a seat occupant""s pelvic region and a reaction plate to which the headrest assembly is secured that pivots and moves upwardly when the lower target is contacted.
The reaction plate is slidably attached to the upper end of the lower target and is attached to the sides of the seat back frame by pivoting links. Apertures formed on the reaction plate are aligned with holes formed on an upper cross member of the seat back frame. The apertures receive bushings that slidably receive a pair of headrest posts of the headrest assembly. The headrest posts extend through the holes in the upper cross member of the seat back frame and apertures in the reaction plate.
The headrest assembly is retained in a normal position generally in line with the seat back. Upon rear impact of the vehicle, the cushion portion of the headrest assembly is moved toward the head of the occupant to an actuated position that is raised and forward of the normal position to provide additional support to the head of the occupant sooner than if the headrest assembly were to remain fixed relative to the seat back. The cushion portion of the headrest assembly is moved toward the head of the occupant in response to the application of a rearward load by an occupant""s pelvis on the lower target. As the upper portion of the lower target pivots rearwardly it applies a force to a lower portion of the reaction plate below a pivot axis of the linkage that connects the reaction plate to the seatback. The lower portion of the reaction plate shifts backwardly and upwardly. The upper portion of the reaction plate moves forwardly and upward carrying with it the headrest cushion.